Electromagnetic sewing machine



v 26, 1940. M, NAUL 2,223,330 ELECTROMAGNETIC SEWING MACHINE,-

Filed Oct. '7, 1959 4 Sheets-Sheet l ww hm HHMH,

Nov. 26, 1940. J; M NAUL.

ELEcTRoMAGNETlc SEWING MACHINE Filed oct. 7, 1959 4 Sheets-Sheet 2 gwuem/bofn James M jVau/l Nov. 26, 1940. J. M NAUI.'

ELECTROMAGNETIC SEWING MACHINE Filed Oct. 7, 1939 4 Sheets-Sheet 3 Nov. 26, 1940. J. M. NAUL 2,223,330

ELECTROMAGNETIC SEWING MACHINE Filed oci. '7, 1939 4 sheets-sheet 4 Patented Nov.n y iti-t@ hLECh/iiinlmilll@ i' n im .l hil. Noni, Funwood, N. t., sor Sinner ltilnnulnc Comun w if' N.; l., n corntion oi New .te i

nnnliion @cto 7, i939,

r m f` No. @925,351

(Cil. lim-269) il. flv

ing the machines jumpy and noisy in operation. Y

The in View ere attained by interconmeeting the upper sind lower machine ec s by means of electrically chronined ro tory devices which maintain a predete im; phase or timed reletionship to one another in-2 denendentfoi speed, yso that the se mechas nisms, such es the upper or needle-drin mechanism and the lower or loop-taking end/or work feeding mechanismsoperate in properly timed relation to one enother without mechanicel connection between said upper end lower mecha.'a nisms.

The invention will be better understood toy re ierring to the accompsg drswinns, of 'which Fie. l is a front elevation, partly in section, of

a se mace Y emlcg the invention. Fig. 2 is o bottom plan view civ the 'mi Fig. 3 is a front end elevation of the machine. Fig. 4 is a rear end elevation oi the niece. Fig. 5 is a transverse section through one oi ythe electrically synchronized twin rotary devices used to coordinate the upper and lower mechanisms of the machine. Fig. 6 is a longitu section through the device of Fie. 5. Fin. 7 is a section on the line '|'l, Fig. 6. Fig. 8 is a sec-V tion, on an enlarged scale, on the line 3-83, 2, and Fig. 9 is a diagram oi the electrical means used to synchronize and time the mechanisms oi the present sewing machine.

The machine is constructed with a frame includlng the hat bed I from one end of which rises the hollow standard 2 of the overhanging bracket-arm 3 terminating in the head 4 which carries the usual reciprocatory needle-bar 5 and spring-pressed presser-bar 6 tted, respectively, with the needle l and presser-foot 8.4 The head l also houses "the usual link take-up 9. The take-up 9 and needle-bar I are operated vin the usual manner by cranks I0, I l on the top rotary shaft I2 which is journaled in bearings i3, I in the overhanging bracket-arm 3.

Complmental to the needle 'l in the formations! stitches is a loop-taker in the form oi a conventional two-to-one rotary hoolr it containing the hobhin-thr tr it restrained against rotation with the hoch it by we conventional hobbin-case rotation-restaurer it', Fis. 2. The rotary hools it is moun on the botto shalt il which is journaled in the or it, it below the il.

ln order for the ne l end rotary hoolr lo to function to iorm stitches, e predeteed timed relationship must he maintained between them at ell times. ln the nresent machine t predeteed timed relation; is maintained 'electricelly and without mechanical connection between the top-shaft it sind bottom-shaft il. Use is herein mode oi selsyn devices to tie the top and bottom shafts it vsind il together in predetermined timed relationship.

The top selsyn A functions as e transmitter oi power and the hottom .1. E iunctions se a receiver of power from the transmitter.

is selsyns A and B are of identical cotruction, s description ci one will sumce The Selsyn, Fiss. 5, t end 7 comprises n 'ousted statorwore 2t which is held in e. frame 2i provig hearings it, it, lor s, it it csr uf- ;-y f. i, shuttle-shaped rotor core @t whic is excited with alteting current hy the two:- oole tvinf` :i 2t the teals oi which sre connected to the slip-s il on the rotor shaft it. Bearing uponI the sliper nre the lo 2t to which nre connected the leads til m n to an eltetine` current supply source. The ststor-core it is wound with a conventional 2 pole 3-phase winding 30. As shown in Fig. 9, the rotors of the i A and B are connected in parallel to the same source oi alternating current, while the three-phase dinss of the' stators of the two yns are connected together by the three wires 3l.

The shaft 24a oi' the top Selsyn A (Figs. l and 4) is coaxial with and is keyed to the top rotary shaft l2 and to the short ft 32 which carries the balance-wheel 33 carrying the belt-pulley 34 connected bythe belt 35 to the pulley 38 of a conventional sewing machine driving motor 31.

When the rotors of Selsyns A and B are exhalf its pitch diameter upon the hook-shaft l1, whereby the hook-shaft I1 is driven at twice the speed of and in time with the top shaft l2. The frame of Selsyn A is secured by screws a, a, Fig. 1, to the standard 2. The frame of selsyn B is secured by screws b, b to the under side of the bed I.

The work-feeding mechanism comprises the 'feed-dog 40 which is carried by the feed-bar 4I pivoted at 42 on the feed-rocker 43 which includes the feed-rock-shaft 44 journaled on the pintles 45. The feed-bar 4| has its forward end a depending portion 46 which is forked to embrace the feed-lift cam 41 on the bottom rotary shaft 24b of Selsyn B. Clamped to the feed-rock-shaft 44 is an arm 48 which extends forwardly and is slotted to embrace the feed-advance cam 419 on the bottom rotary shaft 24b of Selsyn B. The cams 4'! and 49 are feed-actuating members; and are both mounted directly on the shaft 24J of Selsyn B.

ATo minimize hunting tendencies between the Selsyn rotors 25 there is preferably loosely and frictionally mounted on the shaft Il a small iiywheel 50, the frictional drag of which upon the shaft Il depends upon the pressure thereagainst of the spring 5I whose tension is regulated by turning the nut 52. This slip-jointed flywheel steadies the rotor of the receiving Selsyn B so that it will not hunt or oscillate relative to the rotor of the transmitter A.

If the Selsyns A and B are large enough to possess adequate torque characteristics, the departure from exact phase relationship between the two rotors under variable sewing conditions will not be enough to interfere with the formation of stitches by coaction of the loop-taker or rotary hook with the needle.

The invention is not to be understood as limited to any particular type of sewing machine, either lock-stitch or chain-stitch. It is useful in electrically timing the stitch-forming and workfeeding instrumentalities of a sewing machine without regard to the form of the sewing machine frame and without mechanically interconnecting the mechanisms within such frame. Various modifications may obviously be made in the construction and relative arrangement of parts of the machine shown and described, within the spirit of the invention.

Having thus set forth the nature of the invention, what I claim herein is:

1. A sewing machine having a top shaft, a needle driven thereby, a bottom shaft, loop-taking mechanism driven by said bottom shaft, and electrically interconnected Selsyns each having a stationary and a rotary member, said rotary members being mechanically connected to said top and bottom shafts, respectively, means to drive one of said shafts, and a flywheel frictionally driven by the other of said shafts.

2. A sewing machine having a top shaft, a

needle driven thereby, a bottom shaft, a looptaker driven by said bottom shaft, a pair of alternating current energized, two-pole rotors includ- -ing shafts mechanically connected, respectively, to said top and bottom shafts, and a pair of twopole polyphase stators surrounding said rotors and having their winding terminals connected together.

3. A sewing machine having a top shaft, a needle driven thereby, a bottom shaft, a two-to one rotary hook on said bottom shaft, a pair of alternating current energized, two-pole rotors including shafts the upper one of which is connected to the top shaft and the lower one of which is connected at one end by gears to drive4 the bottom shaft two-to-one, feeding mechanism including feed-lift and feed-advance eccentrices on the other end of the lower rotor shaft, and a pair of two-pole polyphase stators surrounding said x'o-v taker complemental to said needle, a loop-takerdriving shaft connected to rotate with the other of said rotors, and means to drive one of said shafts.

5. A sewing machine having a needle, a needledriving shaft, a loop-taker, work-feeding mechanism including feed-actuating members, a Selsyn `system including a pair of polyphase stators and a pair of two-pole alternating current energized rotors including rotor shafts journaled in the respective stator frames, one of said rotor shafts being mechanically connected to the needle-driving shaft and the other rotor shaft being mechanically connected to the loop-taker, and feedactuating members.

6. A sewing machine having a bed and an over-hanging gooseneck, a top shaft in said gooseneck, a reciprocatory needle driven by said top shaft, a rotary loop-taker complementary to said needle in the formation of stitches, a bottom shaft to drive said loop-taker, a transmitting Selsyn motor including a rotor connected to run with said top-shaft, a receiving Selsyn motor having its eld frame mounted below the sewing machine bed, a rotor shaft journaled in the eld frame of the receiving Selsyn and having its two opposite ends projecting beyond said field-frame, a gear on one end of said rotor shaft connected to drive said loop-taker shaft, a feed-cam mounted on the other end of said rotor shaft, and a feedbar in said sewing machine connected to receive feed-and-return movements from said feed-cam.

JAMES M. Neun 

